Walker

ABSTRACT

Since the moving unit comprises a wheel that supports a body portion in a condition that the body portion can be moved, a supporting member that is mounted at a position that does not interfere rotation of the wheel in a condition that can be rotatably driven and an arm that is mounted at a position shifted from an axis of the supporting member and that can move a distal end of the arm toward a direction away from the axis of the supporting member by being driven with the supporting member as a foothold and is so arranged that the body portion can be lifted up together with the wheel by grounding the distal end of the arm when the moving unit is transported, the crank and the arm are incorporated around an axle of the wheel in a compact state, which makes it possible to operate the moving unit stably.

FIELD OF THE ART

[0001] This invention relates to a moving unit that can be utilized as atransporting unit, care aid equipment, walking aid equipment,rehabilitation training equipment, an electric wheelchair or awheel-moving robot.

BACKGROUND ART

[0002] (1) Varieties of moving units have been developed. For example, aforklift, a lifter or a handcart is well-known as a moving unit fortransporting goods and a wheelchair is well-known as a moving unit fortransporting a person.

[0003] However, all of passages where the moving unit moves are not flatand there might be a staircase or an obstacle on the passage. Then it isdifficult for the moving unit having a wheel to move over a leveldifference whose height exceeds a radius of the wheel.

[0004] In order to make it possible for a moving unit having a wheel tomove on a passage having a level difference, a level differenceovercoming mechanism in which a multi-joint link or the like isincorporated has been developed so as to lift up a body portion of themoving unit.

[0005] However, the multi-joint link has a large number of components,which makes is difficult to downsize a body portion. Especially for amoving unit that transports a small package with two wheels driven it ispreferable to incorporate the level difference overcoming mechanism intoa body portion in a compact state.

[0006] The present claimed invention intends to realize a moving unitthat is provided with a function which can serve as a role of a leveldifference overcoming mechanism and can be applied to other diversity ofusages as well.

[0007] (2) Conventionally, in order to make it possible for a machine tomake an up and down movement to go up or down a level difference such asa staircase, the machine is provided with a mechanism of the up and downmovement which has previously been designed to make a specific movementin accordance with a shape of a level difference or the machine isloaded with a camera so as to recognize a level difference by an imageprocessing.

[0008] However, for a case that the up and down mechanism has beendesigned in accordance with a shape of the level difference, a range ofa level difference with which the up and down mechanism can deal isrestricted and it becomes difficult to cope with a diversity of shapesof level differences, which leads to a problem such as that it does notfunction sufficiently and it is difficult to secure safety.

[0009] For a case of image processing, there is a problem that itrequires a complicated and advanced signal processing and that accuracyin detecting the level difference is not high in spite of thecomplicated and advanced signal processing required.

DISCLOSURE OF THE INVENTION

[0010] (1) In order to solve the problem a moving unit of the presentclaimed invention comprises a wheel that supports a body portion in acondition that the body portion can be moved, a supporting member thatis rotatably mounted at a position that does not interfere rotation ofthe wheel in a condition that can be driven and an arm that is mountedat a position shifted from a rotational center of the supporting memberand that can move a distal end of the arm toward a direction away fromthe rotational center of the supporting member by being driven with thesupporting member as a foothold, and is characterized by that the bodyportion can be lifted up together with the wheel by grounding the distalend of the arm when the moving unit is moved. It is especiallypreferable that the supporting member is mounted on the same axis as anaxle of the wheel in order not to prevent rotation of the wheel.

[0011] With the above arrangement, it is possible to move a position atwhich the arm is supported by the supporting member within a movablerange if the supporting member is rotated around the axis on which thesupporting member is mounted. If the distal end of the arm whosesupported position has been moved is driven by a supporting member so asto move toward a direction away from the axle, the body portion can belifted up to a position where a level difference can be overcome bymaking use of reaction when the distal end of the arm touches acorresponding face every time the arm moves. Especially, in case thatthe supporting member is arranged to have the same axis as that of theaxle of the wheel, the arm also rotates around the axle of the wheel. Asa result, there is no need of considering interference among thesupporting member, the arm and the axle of the wheel and it becomespossible to incorporate the arm and the supporting member around theaxle in a compact state. It is a matter of course that the leveldifference overcoming mechanism can be arranged on a position a littleshifted from the axle.

[0012] It is preferable that a driving system that drives the supportingmember and a driving system that drives the arm are arranged so thateach of the driving systems operates independently.

[0013] In accordance with the arrangement in which each of the arm andthe supporting member is driven by a different driving system, it ispossible to operate the supporting member and the arm independently,which makes it possible to operate the supporting member and the armoptimally based on a height of a level difference so as to minimize anup and down movement of the moving unit. As a result, jolt that isapplied to a load or a nursed person (in case of a wheel chair) becomessmall and force that is applied to the handle also becomes small. Inaddition, in case the moving unit is utilized as care aid equipment, itis possible to reduce a load for a cared person and a care person aswell.

[0014] Especially, if the arm is arranged to be grounded near a positionwhere the wheel is grounded, it becomes possible for the center ofgravity to move less when the load is transferred from the wheel to thearm, thereby to make a movement of transferring the load smooth andeffectively to prevent unstable condition due to force occurring in amoment of transferring the gravity as well.

[0015] As a result of this, since the moving unit of the present claimedinvention has a pair of parallel wheels as a driving wheel and the bodyportion is supported by an operator through the handle while moving apassage having a level difference, it can be extremely preferable toreduce a load for an operator.

[0016] As a concrete arrangement of the arm it is preferable that thearm is in a vertical posture and at least a distal end of the arm isaccommodated within a diameter of the wheel when a position where thearm is supported by the supporting member locates vertically above theaxle of the wheel and that the arm moves toward a direction to projectthe distal end of the arm out of the diameter of the wheel when theposition where the arm is supported by the supporting member moves awayfrom the above position.

[0017] In order to make it possible to rotate a position at which thearm is supported at 360 degrees without interfering a movement of thewheel when the arm and the supporting member rotates together with thewheel it is preferable that each of the arm and the supporting member isin a shape that can be accommodated within a diameter of the wheel.

[0018] It is a matter of course that the moving unit can be utilized asobjects or usages other than overcoming a level difference by making useof the above-mentioned fundamental movement.

[0019] (2) In addition, a moving unit of the present claimed inventioncomprises a wheel that supports a body portion in a condition that thebody portion can be moved, a supporting member that is mounted at aposition that does not interfere rotation of the wheel in a conditionthat can be rotatably driven and an arm that is mounted at a positionshifted from an axis of the supporting member and that can move a distalend of the arm toward a direction away from the axis of the supportingmember by being driven with the supporting member as a foothold and ischaracterized by that a detecting means is provided at a side where thearm is grounded so as to measure a shape of level difference by movingthe detecting means with an operation of the arm in the leveldifference.

[0020] With this arrangement, a separately provided detecting means isnot required since the arm that is used for an up and down movement canbe utilized as the detecting means and an advanced processing such as animage processing is not required as well, resulting in providing asimple and secure function of overcoming a level difference. Inaddition, since this moving unit makes use of a continuous movement ofthe arm that makes an up and down movement in order to detect a leveldifference, it is possible to detect the level difference effectively.Further, it only requires the arm be controlled in accordance with thedetected level difference, which makes it possible to deal with adiversity of level difference simply and securely.

[0021] Especially it is preferable that the supporting member and thearm are arranged to gather around a center between the facing wheels.With this arrangement, it is possible to provide the moving unit as faras there are at least a set of a supporting member and an arm, therebyto improve safety for a person who is around the wheel.

[0022] It is preferable that a grounding portion of the arm isark-shaped and so arranged to roll over the ground. With thisarrangement, since a position where the body portion is supported movesfrom the wheels to the level difference through the arm smoothly, forceapplied to the handle and fluctuation of force applied can be made smallas well. Further, since rotation of the arm propels the body portion tomove forward (backward), force that is to be applied forward (backward)by the operator will be made small when the moving unit moves in apassage with a level difference, thereby to lessen a load for theoperator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a schematic view showing a first embodiment of thepresent claimed invention in a condition of being used.

[0024]FIG. 2 is a front view showing a principle portion of theembodiment.

[0025]FIG. 3 is a cross-sectional view of the FIG. 2.

[0026]FIG. 4 is an explanatory view of operation of the embodiment.

[0027]FIG. 5 is a view showing a modified form of the present claimedinvention.

[0028]FIG. 6 is a view showing another modified form of the presentclaimed invention.

[0029]FIG. 7 is a rear view of a moving unit in accordance with a secondembodiment of the present claimed invention.

[0030]FIG. 8 is a side view of the moving unit.

[0031]FIG. 9 is a view showing a detecting means of the embodiment.

[0032]FIG. 10 is an explanatory view of a function of the detectingmeans.

[0033]FIG. 11 is an explanatory view of an operation of the moving unit.

[0034]FIG. 12 is an explanatory view of an operation of the detectingmeans.

BEST MODES OF EMBODYING THE INVENTION

[0035] The invention will be described in detail with reference to anembodiment thereof shown in the accompanying drawings.

[0036] <First Embodiment>

[0037] A moving unit of a first embodiment shown in FIG. 1 is soarranged that a body portion 1 from which a handle 11 is projected issupported by a pair of wheels 2 in a condition of being able to move andthe body portion 1 can carry and transport a load W with the handle 11grasped. A level difference overcoming mechanism 3 is incorporated so asto lift up the body portion 1 together with the wheels 2 to a positionwhere a level difference is overcome when the moving unit is required toovercome the level difference.

[0038] The level difference overcoming mechanism 3 mainly comprises, asshown in FIG. 2 and FIG. 3, a crank 4 as a supporting member and an arm5 that is supported by the crank 4.

[0039] In mounting the crank 4, a pipe member 22 is fitted over an outercircumference of an axle 21 in a relatively rotatable condition and eachof the axle 21 and the pipe member 22 can be rotatably driven throughgears 21 a, 21 b or gears 22 a, 22 b by a motor 21 c, 22 c respectively.A component shown by a numerical code 22 x is a bearing.

[0040] The crank 4 has a shape of a disk that is mounted on a distal endof the pipe member 22 in an integrally rotatable condition and a centerof which provided is a through hole 41 through which the axle 21 passesand a distal end of the axle 21 projects from the through hole 41 so asto axially mount a first gear 61. A drum 43 is rotatably mounted on anappropriate position of the body portion 1 through a bearing 42, a tire20 is mounted on an outer circumference of the drum 43 that constitutesthe wheel 2, a motor 44 c is connected with the drum 43 through gears 44a, 44 b and the tire 20 can be rotatably driven together with the drum43 by the motor 44 c.

[0041] The arm 5 is mounted on a position shifted from a rotatablecenter of the crank 4 through an axle 51 so as to be able to rotate neara proximal end 5 a of the arm 5 wherein a second gear 62 is axiallymounted on the axle 51 and the second gear 62 gears with the first gear61 circumscribably. A grounding body 50 is mounted on a side of a distalend 5 b of the arm 5. The grounding body 50 is generally in a shape of acocoon whose outer circumference is an arc whose diameter equals to adiameter of the wheel 2 minus α and is so arranged that the groundingbody 50 provided on the distal end 5 b of the arm 5 can make a rockingmotion back and forth without making a contact with ground when the axle51 of the arm 5 locates at the highest position with the wheel 2 placedon the ground (refer to FIG. 2) irrespective of a posture or an anglethe body portion 1.

[0042] As is clear from the above explanation and the drawings, adriving system that drives the crank 4 and a driving system that drivesthe arm 5 are arranged so that each of the driving systems operatesindependently as shown in the drawings.

[0043] Next, a method of handling the moving unit will be explained. Incase the moving unit moves on an ordinary flat passage, the moving unitmoves by driving the wheel 2 with the arm 5 kept in a state shown inFIG. 2. At this time the arm 5 is stored in a position where a centerline L of the arm 5 coincides with the line passing the center of thecrank 4, namely, the center of the axle 21 and the arm 5 does notcontact with a face of the passage even though the crank 4 rotatestogether with the wheel 2.

[0044] In case there is a level difference in the passage, the movingunit stops before the level difference as shown in FIG. 4(a) and drivesthe motor 21 c. At this time the second gear 62 makes a planetarymovement around the first gear 61 and the arm 5 whose proximal end ismounted on the second gear 62 rotates counterclockwise so as to move thegrounding body 50 away from the axle 21. Then a part of the groundingbody 50 is grounded near a position where the wheel 2 is in contact withthe ground. Next, drive the motor 2 c so as to rotate the crank 4mounted on the pipe member 22 counterclockwise. At this time the secondgear 62 is fixed through the arm 5, then the first gear 61 makes aplanetary movement around the second gear 62 so as to lift up the axle21 along an ark whose center is the axle 51 of the second gear 62 (FIG.4(b)). During this process all the operator of the moving unit has to dois just grasp the handle 11. After the axle 21 is lifted up to a certaindegree, the operator pulls forward the handle 11 provided with the bodyportion 1 (FIG. 4(c)) so as to ground the wheel 2 on an upper level(FIG. 4(d)) and then the arm 5 is lifted up. In order to lift up the arm5 the motor 21 c is driven until the center line L of the arm 5coincides with the line where the axle 21 passes as shown in FIG. 2. Fora case there are continuous level differences, conduct the aboveoperation repeatedly, and for a case there is a lower level difference,operate the level difference overcoming mechanism 3 reverse to the aboveoperation.

[0045] As mentioned above, since the moving unit of the embodiment hasan arrangement in which the crank 4 is mounted on the same axis as theaxle 21, a position where the arm 5 is supported by the crank 4 can bemoved around the axle 21 if the crank 4 is rotated around the axle 21.If the grounding body 50 mounted on the distal end of the arm 5 whosesupported position (the axle 51) has been moved is driven to move towarda direction away from the axle 21 by making use of the crank as afoothold, the body portion 1 can be lifted up to a position where alevel difference can be overcome by making use of reaction every timethe grounding body 50 touches a corresponding face to be grounded whenthe grounding body 50 moves. As mentioned above, since the crank 4 isarranged on the same axis as the axle 21 and the arm 5 rotates aroundthe axle 21, there is no need of considering interference of the crank 4or the arm 5 with the axle 21 and a range in which the arm 5 moves canbe made small. As a result, the level difference overcoming mechanism 3can be incorporated in a compact state around the axle 21, thereby toincrease an amount of capacity and to effectively improve safety.

[0046] Especially, if the arm 5 is arranged to be grounded near aposition where the wheel 2 is grounded, a movement of a center ofgravity can be made small when a load is transferred from the wheel 2 tothe arm 5, thereby to make a movement of transferring smooth andeffectively to prevent unstable condition due to force occurring in amoment of transferring the gravity as well. Especially, in accordancewith the moving unit of this embodiment the level difference overcomingmechanism 3 is driven in a condition that a pair of wheels arranged inparallel are placed on the ground and one end of the moving unit isgrasped with the handle 11, thereby to minimize fluctuation of forcethat supports the moving unit. This contributes to lessening load tooperate the handle for the operator.

[0047] Especially since the arm 5 is so arranged when a position wherethe arm 5 is supported by the crank 4 locates vertically above the axle21, the arm 5 is in a vertical posture and at least a distal end of thearm 5 is accommodated within a diameter of the wheel 2 and when theposition where the arm 5 is supported by the crank 4 moves away from theabove position, the arm 5 moves toward a direction to project thegrounding body 50 out of the diameter of the wheel 2, the grounding body50 of the arm 5 can be moved to an arbitrary position irrespective of aposture (angle) of the body portion 1 within a total length of the crank4 and the arm 5. As a result, the arm 5 can be grounded at the optimumposition irrespective of a posture of the body portion 1 in leveldifference, thereby to lessen fluctuation of force that supports themoving unit in a situation of a diversity of level differences, whichmakes it possible to make a smooth and stable up-and-down movement.

[0048] Since the arm 5 and the crank 4 can be accommodated within adiameter of the wheel 2, neither the arm 5 nor the crank 4 disturbs amovement of the wheel 2 when the arm 5 and the crank 4 rotate togetherwith the wheel 2, which makes it possible to rotate a position at whichthe arm 5 is supported at 360 degrees.

[0049] Further, in a passage without level differences it is possible tomake use of the arm 5 for a diversity of usages such as loading orunloading.

[0050] It is a matter of the fact that the arrangement of this inventionis not limited to the above-mentioned embodiment. For example, basicallya number of the wheels is a parallel two, however, it may be one, threeor four.

[0051] Whether there is a level difference or not or a height of thelevel difference may be detected by the use of a limit switch or aproximity sensor and an angle or a posture of the level difference maybe detected by the use of a rotary encoder or a gyroscope toappropriately control the level difference overcoming mechanism.

[0052] The driving system can be commonized with a clutch or a breakprovided between each of the axles. For example, a wheel and a crank maybe switched to drive with a single motor. Or a pair of parallel wheelscan be driven through a differential gear like an automobile.

[0053] Force to drive the arm may be transmitted through an idler gearor a chain in addition to direct transmission between the first gear andthe second gear. A driving system of the arm can be incorporated intothe crank.

[0054] The gear may be arranged inner side of the crank locatingopposite to the arm. In this case, the pipe member drives the first gearand the axle of the wheel drives the crank.

[0055] The second gear 62 may be in a shape of a rack, as shown in FIG.5, and the rack can be used as an arm 105. In this case, if the rack issecured to extend upward so as to broaden a range within the arm 105 canmove, it becomes possible to overcome a higher level difference. 105 adesignates a guide roller that guides the arm 105 to make a linearmovement.

[0056] As shown in FIG. 6, an arm 205 that is curved along a half circlecorresponding to a diameter of the wheel 2 may be used. In this case,the arm 205 is not symmetry, however, a range within the arm 205 canmove is broadened, which makes it possible to rotate the arm 205continuously to a rotation of the wheel 2 before a level difference,thereby to lift up the wheel 2 smoothly like climbing a slope. Inaddition, since it is possible for the arm 205 to avoid interferencewith the wheel 2 due to a concave portion 205 a of the arm 205, the arm205 can be arranged in a side of the axle 21 of the wheel.

[0057] An end effector (an adaptor) such as a shoe, an auxiliary wheel,a fork, a hook, a toe (a second arm) or a hand may be mounted on the armso as to be selected in accordance with a shape of a load or a conditionof transportation. The operation of changing the end effector may beautomated with an operation of the arm.

[0058] As shown in FIG. 1, an auxiliary wheel of a caster type may bemounted in front of the body portion. It is also effective if a stopperof a hinge type is provided below and in front of the body portion 1 soas not to incline the moving unit exceeding a limit in a safety range ofan inclining angle with the stopper grounded when the body portion 1inclines downward exceeding the limit.

[0059] In case there is a level difference, a load carrier may beinclined so as to lower a center of gravity. The handle may be elongateda little so as to operate at a place a little away from the bodyportion.

[0060] In addition, a step may be provided at a rear of the body portionso as to carry an operator.

[0061] A level difference and a height of the level difference may bedetected from an image processing by the use of a CCD camera so as todrive the arm. In this case, it is possible to set the arm in theoptimum phase while approaching a level difference, thereby to overcomethe level difference without breaking a movement.

[0062] In case a load is a person, a support jig may be used to supportan elbow, a shoulder or a waist of the person.

[0063] The moving unit can be used as walking aid equipment if a seatcan be recessed rear of the body portion, an armrest can be held upwardthrough a spring and the armrest can support a part of the weight of aperson while his or her foot is grounded. The arm may hold the spring.

[0064] It is possible to control supporting force or a direction to bemoved by detecting force that is applied to the spring. In case there isa level difference, return a position of the seat and the armrest, siton the seat and operate the arm like the above mentioned embodiment.

[0065] The moving unit can be applied to a diversity of equipment suchas a substitute for wheelchair, care aid equipment, aid equipment forsitting or standing up or rehabilitation equipment.

[0066] The moving unit also can be applied to a diversity of travelingrobots that requires high reliability to overcome a level difference.Especially, when the moving unit is applied to a robot, the robot canstand up again by itself by the use of the arm in case it overturns.

[0067] In addition if the arm is placed a little out of the wheel whilethe wheel rotates, a pitch per rotation can be changed. The wheel can berotated through the arm. In case there is a level difference, the wheelmay be made to contact a side face of the level difference, then thebody portion may be lifted up and the wheel may be rotated with thewheel pushing against the side face of the level difference. Further,the arm can be pulled up in a condition that the arm contacts with theside of the level difference not to rotate the body portion or the armcan be pulled up by making use of reaction to restore its posture whenthe body portion is pushed forward.

[0068] It is a matter of course that the moving unit can be utilized asobjects or usages other than overcoming a level difference by making useof the above-mentioned fundamental movement.

[0069] Other arrangement may be variously modified without departingfrom a spirit of the invention.

[0070] <Second Embodiment>

[0071] The embodiment is shown in FIG. 8 wherein a body portion 1 issupported by a pair of wheels 2 in a condition that the body portion canbe moved and above the body portion 1 arranged is a seat 3 on which aperson can sit.

[0072] The moving unit comprises, as shown in FIG. 7 and FIG. 8, theabove-mentioned wheels 2, a crank 6 as a supporting member that isrotatably mounted at a position that does not interfere rotation of thewheels 2 and an arm 7 that is mounted at a position shifted from arotational center of the crank 6 and that can move a distal end of thearm 7 toward a direction away from the rotational center of the crank 6by being driven with the crank 6 as a foothold.

[0073] The body portion 1 is provided with a motor 4 for driving thecrank 6 and a motor 5 for driving the arm 7 each of which is arranged onthe same axis of a pair of flanges 1 a, 1 b each spaced apart at apredetermined distance and each of which can be driven independently.

[0074] A proximal end of the crank 6 is fixed to the motor 4 for drivingthe crank 6 and a distal end of the crank 6 is elongated so as to rotatearound the axis between the flanges 1 a and 1 b.

[0075] A proximal end of the arm 7 is axially connected with the distalend of the crank 6 through a level axle 8, a distal end of the arm 7 isbifurcated and a grounding member 12 that has a partial arc-shaped faceto be grounded is mounted on each of the bifurcated distal ends of thearm 7. The grounding member 12 as a portion of the arm 7 that is to begrounded is arc-shaped and makes a movement like rolling on the ground.

[0076] A gear 10 is fixed to a projecting end of the level axle 8 andthe gear 10 is connected to the gear 9 mounted on the axle 5 a of themotor 5 for driving the arm 7 through a chain 11.

[0077] More specifically, the crank 6 can be driven by the motor 4 fordriving the crank 6 and the arm 7 can be driven by the motor 5 fordriving the arm 7. The crank 6 and the arm 7 are incorporated in acondition of being gathered to a center between two wheels 2, 2.

[0078] In this embodiment the grounding member 12 of the arm 5 isprovided with a detecting means 13 and in case there is a leveldifference, a shape of the level difference is measured by moving thedetecting means 13 with the arm 7 operated.

[0079] More specifically, the detecting means 13 is arranged at a rearside of the grounding member 12 and comprises, as shown in FIG. 9, asmall wheel 14, a bar 15 on a distal end of which the small wheel 14 isaxially mounted and a proximal end of which is supported through a pin16 in a condition of being able to rock, a first limit switch 17 thatdetects a direction to which the bar 15 rocks, a linear guide 18 thatsupports the first limit switch 17 in a condition that the first limitswitch 17 can make a linear movement and a second limit switch 19 thatdetects a linear displacement of the linear guide 18, namely a lineardisplacement of the small wheel 14.

[0080] Whether or not the wheel 2 makes a contact with an object to bedetected is detected through the second limit switch 19 and a horizontaland vertical position of the small wheel 14 relative to the wheel 2 canbe measured with a rotational angle of the crank 6 and the arm 7 and astate of the first limit switch 17 (namely, a rocking angle of the bar15). More specifically, the detecting means 13 is able to detect arelative position of the grounded portion appropriately in accordancewith a state of the grounding member 12 not only in a state that the bar15 does not make a rocking movement as shown in FIG. 10(c) but also in astate that the bar 15 makes a rocking movement as shown in FIG.10(a),(b). The reason why the bar 15 is made to be able to make arocking movement is to avoid an excessive load that might be applied tothe detecting means 13 during an up and down movement when the smallwheel 14 receives reaction from a point with which the small wheel 14makes a contact and the bar 15 makes a linear movement to a certaindegree by making the detecting means 13 recessed with surroundings ofthe grounding member 12 contact with the point due to a rocking movementof the bar 15.

[0081] Next, a movement of going up a level difference by the use of themoving unit having the above arrangement will be explained withreference to FIG. 11 and FIG. 12.

[0082] First, drive the arm 7 through the crank 6 so that the smallwheel 14 of the detecting means 13 arranged on the grounding member 12of the arm 7 draws a track along a circle whose a diameter is a littlelarger than an outer diameter of the wheel 2 after the wheel 2 makes anabutting contact with an upper level as shown in FIG. 12(a). Detect anedge between a lower level and the upper level by means of the detectingmeans 13 at an instant when the small wheel 12 becomes free after thesmall wheel 14 makes an abutting contact with a front wall of the upperlevel and is separated from the front wall and measure a distance to theupper level and a height of the upper level from an angle of the crank 6or the arm 7. Determine a condition of driving the arm 7 and the crank 6for going up the level difference based on the distance and the heightobtained in the above procedure.

[0083] Specifically, a method of driving the arm 7 and the crank 6 is;drive a motor 5 for driving the arm 7, transfer driving force to the arm7 through the chain 11 and the second gear 10 so to move the arm 7 andground the grounding member 12 (FIG. 11(a)).

[0084] Next, drive the motor 4 for driving the crank 6 so as to move thegrounding member 12 mounted on a distal end of the arm 7 toward adirection away from the wheel 2. More specifically, in a condition thatthe grounding member 12 contacts the ground, drive the motor 4 fordriving the crank 6 so as to rotate the crank 6 around the level axle 8on which an upper portion of the crank 6 is axially mounted and to pullthe body portion 1 up to a position where the level difference can beovercome by making use of reaction of the crank 6 (FIG. 11(b)).

[0085] Next, a case the moving unit goes down a level difference will beexplained.

[0086] First, drive the crank 6 and arm 7 so as to move the wheel 2 withthe small wheel 14 of the detecting means 13 arranged on the groundingmember 12 of the arm 7 kept in contact with a floor of the upper levelas shown in FIG. 12(b), and stop the wheel 2 by detecting an edgebetween the lower level and the upper level by means of the detectingmeans 13 at an instant when the small wheel 14 is made free fromreaction from the floor. Next, drive the crank 6 and the arm 7 again soas to ground the small wheel 14 on a floor of the lower level andmeasure a height of the level difference and a distance between thewheel 2 and the small wheel 14 from a reaction that the small wheel 14receives. Determine a condition of driving the arm 7 and the crank 6 forgoing down the level difference based on the distance to the leveldifference, the height of the level difference and a distance to a pointto be grounded obtained in the above procedure.

[0087] Then drive the motor 4 for driving the crank 6 so that thegrounding member 12 mounted on the distal end of the arm 7 graduallyapproaches to an axis of the motor 4 for driving the crank 6, whichmakes it possible for the wheel 2 to be grounded on a floor of the lowerlevel by lowering the body portion 1.

[0088] The motors 4 and 5 are controlled automatically to be on-off by acontrol unit, not shown in drawings, based on a driving conditionobtained from the above measurement.

[0089] The moving unit of the this embodiment does not require any otherdriving mechanism for detecting a level difference since a movement ofthe arm 7 that is used for moving up and down is utilized to detect alevel difference, which makes it possible to detect a level differencesecurely without conducting an advanced processing such as an imageprocessing. In addition, since the moving unit makes use of a continuousmovement of the arm 7 in accordance with an up and down movement, it ispossible to detect a level difference effectively. Further, since all ithas to do is control a movement of the arm 7 in accordance with thedetected level difference, it is possible to deal with a diversity oflevel differences with ease.

[0090] Especially, since both of the crank 6 and the arm 7 are arrangedon the same axis as that of the wheel 2, a relationship between thelevel difference and the wheel 2 is easy to recognize and safety caneffectively be improved with avoiding interference between the arm 7 andthe level difference.

[0091] Further, since a driving mechanism is concentrated on a centralpart of the wheels 2, a number of components can be reduced andreliability can effectively be improved.

[0092] Each of concrete arrangement is not limited to theabove-mentioned embodiment, and there may be various modificationswithout departing from a spirit of the invention.

[0093] For example, an idler gear may be arranged on the crank 6 insteadof the chain 11. In addition, the wheels 2 may be supported by the crank6. Further, the axle 2 a may be made hollow so that the motor 4 can beincorporated thereinto.

[0094] A position where the detecting means 13 is arranged is notlimited to an end portion of the grounding member 12 of the arm 7 butmay be formed to elongate a body portion (a portion before a bifurcatedportion) of the arm 7. The detecting means 13 is not limited to acontact type, but may be a non-contact type such as an optical sensor ora supersonic wave sensor and may also be supported flexibly through aspring. A mechanism of the detecting means 13 is not limited to a switchtype, but may be a displacement instrument, an angle instrument and aload cell that measures contact force and a direction of a leveldifference or may be a combination of the above.

[0095] Further, a load cell may be provided to an operational handle soas to adjust a position of the handle to minimize force applied to thehandle while going up and down or moving with the wheels 2.

[0096] Timing when the wheels 2 make a contact with an upper level canbe detected when a load applied to a motor for driving wheels 2, notshown in drawings, is increased.

[0097] Possible Applications in Industry

[0098] The present claimed invention is embodied in the above-mentionedarrangement and following effects are produced.

[0099] (1) First, in the present claimed invention since the supportingmember that supports the arm is rotatably mounted on the same axis asthat of the axle of the wheel so as not to prevent rotation of thewheel, it is possible to incorporate the supporting member, the arm orother components into the moving unit in a compact state, thereby toeffectively avoid mutual interference of the supporting member, the armwith the axle. A function as a level difference overcoming mechanism caneffectively be produced by making use of movement of the arm and thesupporting member, which makes it possible to utilize the function in abroad range of object such as loading or unloading a load placed near afloor or on a stand, adjusting an angle of a stand or a seat and a guidefor preventing overturn in a slope.

[0100] (2) In addition, the present claimed invention is so arrangedthat a level difference is overcome by extending an arm from a bodyportion and a detecting means is provided at a side where the arm isgrounded so as to measure a shape of the level difference by moving thedetecting means with an operation of the arm in the level difference.

[0101] This arrangement makes it possible that a separately provideddetecting means is not required since the arm that is used for an up anddown movement can be utilized as the detecting means and an advancedprocessing such as an image processing is not required as well,resulting in providing a simple and secure function of overcoming alevel difference. In addition, since this moving unit makes use of acontinuous movement of the arm that makes an up and down movement inorder to detect a level difference, it is possible to detect the leveldifference effectively. Further, it only requires controlling the arm inaccordance with the detected level difference, which makes it possibleto deal with a diversity of level difference simply and securely.

1. A moving unit comprising a wheel that supports a body portion in acondition that the body portion can be moved, a supporting member thatis mounted at a position that does not interfere rotation of the wheelin a condition that can be rotatably driven and an arm that is mountedat a position shifted from a rotational center of the supporting memberand that can move a distal end of the arm toward a direction away fromthe rotational center of the supporting member by being driven with thesupporting member as a foothold, and characterized by that the bodyportion can be lifted up together with the wheel by grounding the distalend of the arm when the moving unit is transported.
 2. The moving unitdescribed in claim 1 wherein a driving system that drives the supportingmember and a driving system that drives the arm are arranged so thateach of the driving systems operates independently.
 3. A moving unitcomprising a wheel that supports a body portion in a condition that thebody portion can be moved, a supporting member that is mounted at aposition that does not interfere rotation of the wheel in a conditionthat can be rotatably driven and an arm that is mounted at a positionshifted from a rotational center of the supporting member and that canmove a distal end of the arm toward a direction away from the rotationalcenter of the supporting member by being driven with the supportingmember as a foothold, and characterized by that a detecting means isprovided at a side where the arm is grounded so as to measure a shape ofa level difference by moving the detecting means with an operation ofthe arm in the level difference.
 4. The moving unit described in claim 2or 3 wherein the a center between the facing wheels.
 5. The moving unitdescribed in claim 1, 2, 3 or 4 wherein a grounding portion of the armis ark-shaped and so arranged to roll over the ground.